Cornelis Heuckeroth, who goes under the stage name of Gordon, made a number of snide comments mocking singer Xiao Wang's ethnicity during Holland's Got Talent, a programme ultimately under the control of Cowell.
"Racism isn't a laughing matter," Avinash Sampath, an Amsterdam-based activist who launched the petition on Change.org website, said.
"This shouldn't be swept under the carpet of 'Oh! This is how we crack jokes in Holland!'
The petition urged Cowell to sack Heuckeroth "for his blatantly racist remarks at Xiao Wang".
"The comments got under my skin," Sampath told IBTimes UK. "It's 2013 and no one deserves to be insulted or mocked because of where they are from. And definitely not on television.
"I understand that Simon Cowell takes personal interest in picking the judges in every country his franchise rolls out in," Sampath said. "So I'm hoping he'll sit up and take notice."
"It's high time to teach Gordon and racist colleagues a lesson. Not having Gordon on TV is generally a good idea for humanity," said subscriber R Coenen.
"I'm utterly ashamed of your show and am not watching any more," added Lachlan Hayman.
Heuckeroth, a 45-year-old Dutch singer turned television presenter, fired a series of cheap shots at Xiao, a PhD business student of Chinese descent before and after his performance.
"Which number are you singing? Number 39 with rice?" Heuckeroth asked Xiao after the contestant announced he was to sing an operatic aria.
"Surplise. Honestly, this is the best Chinese I've had in weeks. And it's not a takeaway," he added after the performance.
A video of the incident was initially posted on YouTube by the show's Dutch broadcasted RTL but was later taken down. It has been reposted by other users.
A spokesman for Fremantle Media, which owns the "Got Talent" franchise, said the company was "trying to get to the bottom" of the incident but had no further comment.
No one at RTL was available for a comment as we published.